Last updated: October 2026
For most common antibiotics, such as amoxicillin, there’s no known interaction with CBD. The main exceptions are antibiotics that affect liver enzymes: rifampicin lowered CBD levels by about 30% in a prescription CBD study, while clarithromycin and erythromycin could raise CBD levels. The simplest option is to pause CBD until your course ends, and ask your pharmacist.
Below: antibiotics by interaction risk, why interactions happen, side effects to watch for, and when to stop CBD.
Antibiotics and CBD: interaction risk
| Antibiotic | Interaction risk with CBD | Why |
|---|---|---|
| Rifampicin (for TB and some serious infections) | Yes | Speeds up CBD breakdown; lowered CBD levels by about 30% in a prescription CBD study |
| Clarithromycin, erythromycin | Possible | Strongly block the CYP3A4 liver enzyme, which could raise CBD levels |
| Fluconazole (antifungal, often given alongside) | Possible | Blocks enzymes that break down CBD |
| Metronidazole | Low with CBD; avoid alcohol | The main warning is about alcohol, including alcohol-based tinctures |
| Amoxicillin, penicillin, flucloxacillin | No known interaction | Mostly cleared by the kidneys, not liver enzymes |
| Doxycycline, nitrofurantoin, trimethoprim | No known significant interaction | Check with your pharmacist if you take other medicines too |
This is a general guide, not a full list. Your pharmacist can check your exact antibiotic and any other medicines. For more, see CBD and medication.
Why interactions happen
CBD is broken down in the liver, mainly by the enzymes CYP3A4 and CYP2C19, and it can slow those enzymes down. Medicines that speed them up (like rifampicin) lower CBD levels, while medicines that slow them (like clarithromycin) can raise CBD levels. CBD can also raise levels of some medicines processed the same way. The same enzyme is behind the grapefruit warning on some medicine leaflets.
Side effects to watch for
- Upset stomach and diarrhoea: common with antibiotics, and also with higher doses of CBD. See CBD side effects.
- Tiredness and dizziness.
- Liver strain: some antibiotics can affect the liver, as can high-dose CBD. See CBD and the liver.
Stop CBD and contact your GP or 111 if you develop yellow skin or eyes, severe diarrhoea, a rash, or feel much worse.
Should you pause CBD?
For a short course of a common antibiotic, many people simply pause CBD for a week or so and restart afterwards. CBD doesn’t cause withdrawal, so stopping is easy. See is CBD addictive? Pause it, or check with a pharmacist first, if you:
- are taking rifampicin, clarithromycin, erythromycin or an antifungal
- take other regular medicines as well
- have liver problems
- feel very unwell or are in hospital
The FSA’s 10mg a day figure is precautionary advice rather than a legal limit, set while longer-term safety research continues. At Evopure we think it is a very cautious figure, and many adults use more. If you go above it, increase slowly, and check with your GP or pharmacist first if you take any medication. Our CBD oils are alcohol-free.
Does CBD fight infections?
In a 2021 lab study, CBD killed some types of bacteria in a dish. That doesn’t mean CBD supplements treat infections, and they should never replace antibiotics. Always finish your antibiotic course as prescribed.
FAQs
Can I take CBD with antibiotics?
With most common antibiotics like amoxicillin, there’s no known interaction. Rifampicin, clarithromycin and erythromycin can affect CBD levels, so ask a pharmacist.
Can I take CBD with amoxicillin?
There’s no known interaction, as amoxicillin is mostly cleared by the kidneys. Check with a pharmacist if you take other medicines.
Does CBD stop antibiotics working?
There’s no evidence it does. The concern runs the other way: some antibiotics change CBD levels.
Can I take CBD with metronidazole?
There’s no known significant interaction with CBD itself, but avoid alcohol, including alcohol-based tinctures, during the course and for 2 days after, as the NHS advises.
Should I stop CBD while on antibiotics?
Pausing for a short course is a simple, safe option, and CBD doesn’t cause withdrawal.
Sources
- Electronic Medicines Compendium. Epidyolex: summary of product characteristics (section 4.5, interactions).
- Balachandran P et al. Cannabidiol interactions with medications, illicit substances, and alcohol: a comprehensive review. J Gen Intern Med, 2021.
- Blaskovich MAT et al. The antimicrobial potential of cannabidiol. Commun Biol, 2021.
- NHS. Common questions about metronidazole.
